Vibration cancellation apparatus

摘要

A compact vibration cancellation apparatus based on a combination of air springs and electromagnetic actuators with smaller power capacity enables an anti-vibration table to be maintained in a level position even when the center of gravity of the anti-vibration table moves a large distance because of a movement of objective equipment on the table. The vibration cancellation apparatus is operable for isolating floor vibration or for canceling vibration of the objective equipment on the anti-vibration table. The apparatus includes displacement sensors, acceleration sensors, a levitation position control device, a vibration canceling control device, and air spring actuators for supporting four corners of the anti-vibration table by air pressure. The air pressure in each air spring actuator is controlled in response to a change of load which corresponds to a movement of the center of gravity caused by movement of the objective equipment on the anti-vibration table.